Gas turbine engines usually include a pressure vessel portion surrounded by a casing receiving compressed air from the compressor section, and into which several devices project, for example fuel nozzles, ignitors, etc. Generally, a plurality of holes are provided in the casing through which such devices extend, with the casing usually being reinforced in the portion around the holes by flanged areas or bosses. The devices, e.g. fuel nozzles, typically include an extending flange which mates with the reinforced portion around the respective hole on the exterior surface of the combustor casing. The reinforced portion and flange may further include additional aligned threaded holes which receive fasteners, such as bolts, to retain the flange to the casing and ensure an adequate seal between the devices and the casing through which they project. The flange and reinforced portion must be thick enough not to distort under the high temperature and pressures to which they are exposed, since the compressed air within the casing will produce a force which acts to separate the flange from the reinforced portion in an attempt to force the device out through the corresponding hole in the casing. Such an “exterior” mounting of the device on the combustor casing requires relatively complex and heavy fastening and sealing means, however is commonly used because of the ease with which such devices can be removed from the outside of the casing if required, for maintenance purposes for example.
Accordingly, there is a need to provide an improved device mounted within a pressure vessel such as are found in gas turbine engines.